The first thing that came to mind is that the art style looks similar to Adventure Quest Worlds, especially in your screenshots with the character in the environment. That style always felt charming to me and its coming through here with your stuff. I actually like your linework better - its got a hand drawn unevenness to it that makes it feel less clean and more animated.
However, your description of the game seems to make the aesthetic out to be more serious. I see someone else commented about the visuals looking like Castle Crashers - which is a charming and goofy style as well. If you want to hold onto this look you will want to shift the tone of your game to be more like the two games mentioned above. Its communicating more of a "jaunty cartoon dungeon crawler" vibe.
If you want to lean into the serious tone - a bit of desaturation and adding heavy blocks of shadows to what you already have might do the trick. Or you could play around with messy textures to add a "grimy" look to things.
Overall you have a great foundation for the style. I'm curious to see how it would look in motion. Great work!